The optimum Maximum Range Cruise (MRC) speed is the speed value which maximizes an aircraft range, for given atmospheric conditions and fuel load, while maintaining the altitude, which is equivalent to minimizing the fuel consumption to reach a certain distance for the given atmospheric conditions. Maximizing the aircraft range includes obtaining the optimum Mach number for a given altitude. Generally the given altitude is provided by an Air Traffic Control (ATC) entity.
Solutions for optimizing maximum range are generally focused on aircraft preliminary design instead of actual flight management system (FMS) implementation or trajectory prediction. Such aircraft preliminary design solutions contain significant simplifications such as ignoring factors (e.g., wind, parabolic drag polar, and constant thrust specific fuel consumption (TSFC)) that make the results inappropriate for the operational use thereof.